For more than two decades, many investigators have tried a variety of methods for delivering antimicrobial agents to the oral cavity with the objective of eliminating mutans streptococci. In the belief that the effectiveness of chemotherapy might be improved by a more effective delivery system, the intention of the present study was to exploit a new drug delivery system delivering chlorhexidine to the oral cavity. The vehicle delivering chlorhexidine tested in this study was self-curing acrylic resin(polymethyl methacrylate). The powder of the acrylic resin was polymerized with the 5 different liquid preparations, in which $Chlorzoin^{(R)}$ was mixed with five different monomer/Chlorzoin ratios immediately prior to the polymerization, in a stainless steel mold ($40mm{\times}40mm{\times}2mm$). A total of 50 cured resin specimens were divided into 5 groups according to the different monomer preparations. Every specimen was soaked in an airtight container filled with distilled water (100 ml) and then kept in an incubator at $37^{\circ}C$. The solutions (0.8 ml) were collected from the container at every 24 hours, and the amount of released chlorhexidine in the solutions was measured in an ultraviolet spectrophotometer at 250nm. The container was refilled with distilled water every after measurement. This procedure was repeated for 14 days. It was found that chlorhexidine was continuously released from all of the 50 specimens during the experimental period. And it was noted that the pattern of chlorhexidine release was a type of sustained-release preparation, that is, the amount of the released chlorhexidine at the first day in all 5 groups was high (p<0.0001), and then the release was decreased during the rest of the experimental period (p<0.001).

낭종은 환자의 연령, 낭종의 종류 및 위치에 따라 치료방법을 선택하는 것이 바람직하며, 환자의 연령이 어린 경우에는 조대술을 통하여 낭종에 이환된 치아를 가능한 보존시키는 것이 바람직한 것으로 생각된다. 낭종에 포함되었던 치아는 조대술로 낭종을 제거후에 생리적인 맹출이 이루어지는 것을 관찰할 수 있었으며 기능도 정상적으로 수행하는 것으로 판단된다. 그러나, 조대술을 이용하여 시술한 후에는 맹출된 치아에 병리조직이 잔존되어 재발의 가능성이 있으므로 주기적인 관찰이 요구될 것으로 생각된다.

For the purpose of comparing the shear bond strengths of pit and fissure sealants, and finding out the more efficient method of tooth surface treatment when the etched surface is contaminaed by saliva or moisture, an experiment was performed on 3 types of pit and fissure sealants. 120 extracted human molars were divided into 3 groups, each of which was composed of 40 specimens sealed with Helioseal, Teethmate-F and Fuji III respectively. And each groups was again divided into 4 subgroups according to tooth surface treatment. The shear bond strengths of each groups and subgroup was measured and statistically analyzed. The results obtained were as follows : 1. Shear bond strengths of nonfluoridated resin sealant, Helioseal were shown to be higher than those of fluoridated resin sealant, Teethmate-F, but, not significantly different. 2. Shear bond strengths of GI sealant, Fuji III were to be markedly lower than those of two resin sealants. 3. When there is moisture contamination, applying primer under sealant(Group IV) results in a significantly stronger bond strength of sealant to enamel than when using sealant alone(Group II) in case of all sealants. 4. When there is no moisture contamination, using primer under sealant (Group III) results in bond strength equivalent to bond strength on using sealant alone (Group I). 5. Based on the results above, it was demonstrated that the bond of sealant to tooth surface is greatly affected by saliva contamination and that the complete tooth isolation method should be fully emphasized. The application of primer is recommended when performing sealant under the environment very susceptible to saliva contamination.

The purpose of this study was to asses the shear bond strengths of 3 types of glass ionomer cement and 1 type of composite resin to dentinal surface with or without ZOE pretreatment. 80 extracted tooth specimens are divided into two groups; the control group (40 specimens) is not treated with ZOE and the other(40 specimens) is ZOE pretreated during 24 hours before bonding procedure. Shear bond strengths were measured with universal testing machine (Instron, Model 4301) and statistically processed by ANOVA and t-test. The results were as follows: 1. Bond strength of the ZOE treated experimental group showed lower than the control group, except chemical cured glass ionomer cement(p<0.05). 2. After ZOE surface treatment, the bond strength of composite resin was superior than glass ionomer cement and all experimental group was decreased (p<0.05). 3. It has nothing to do with ZOE surface treatment, that chemical curing glass ionomer cement was showed lowest bond strength.

The arbitrary primer polymerase chain reaction(AP-PCR) and Southern blot restriction fragment length polymorphism(RFLP) were used to genotype the cariogenic pathogen S. mutans in children. Following the morphologic chracteristics of colony on selective medium for S. mutans, total genomic DNA from 155 strains was extracted by conventional methods. Among 155 strains, 143 strains (92.3%) were confirmed S. mutans by PCR with dexA gene and 114 strains were used in this study. Three random sequence 10-base oligonucleotide primers were chosen for AP-PCR. The amplified DNA products were separated electrophoretically in a 2% agarose gel containing ethidium bromide and the banding patterns were compared among different strains. For RFLP analysis, DNA was digested with EcoRI and BamHI, separated on a 0.7 % agarose gel and transferred to a nylon membrane. The membrane was probed with a previously characterised 1.6 kilobases (kb) DNA fragment cloned from gtf B gene of S. mutans. The probe was labeled with isotope[$^{32}P-{\alpha}CTP$], and hybridized fragments were detected with intensifying screen. AP-PCR produced 4-8 DNA bands in the 0.25-10 kb regions and distinguished 9, 10 or 12 genotypes, depending on the specific primer used. Southern blot RFLP analysis revealed 2 hybridization patterns consisting of 1 DNA fragments 450, 500 bp. These results indicate that AP-PCR is more discriminative method for genotyping of S. mutans.

The purpose of this study was to evaluate the shear bond strength on dentin of bonding agents based on glass ionomer cements, and to establish the appropriate method of bonding which has biological safety and decrease the pulpal damage. Fuji Bond LC, Advance, All Bond 2 and Scotchbond Multipurpose were applicated on occlusal dentin layer in acrylic resin block. Each group was composed of 10 specimens and the shear bond strenth between dentin layer and composite resin was measured with the Universal Testing Machine and analyzed. The result were as follows: 1. When using ANOVA and Scheffe' s multiple range test, there were not statistical differences among the four group. (P < 0.05) 2. The shear bond strength was high in the order of C, D, A. B and bond strength of group B showed relatively lower. 3. In digital image processing, there were not significant differences on morphology of failure surface.

There are many concerns about the erosive effect of acidic beverage. In this study, the erosive effect of bovine enamel caused by $Pepsi-Cola^{(R)}$(pH 2.41) and rehardening effect by intraoral exposure were determined by microhardness test and SEM. The bovine enamel specimen was imbedded in 100ml $Pepsi-Cola^{(R)}$ during 5 minutes and exposed to the intraoral environment with removable resin plate. The microhardness test was performed after 1 hr, 24 hrs, and 48 hrs. The results obtained from this study can be summarized as follows ; 1. The microhardness value was significantly (p<0.05) reduced by cola beverage, and significantly (p<0.05) increased after 1 hr and 24 hrs respectively. 2. The difference in the microhardness between 24 hrs group and 48 hrs group was not significant (p>0.05) and microhardness value of 48 hrs group was significantly less than that of initial group (p<0.05). 3. The erosive effect of cola beverage and remineralization effect by intraoral exposure were visualized by the SEM photo. But, the enamel surfaces did not return to their original state.

The purpose of this study was to compare the microleakage of the amalgam and the gallium alloy when several lining materials were applied. The ANA 2000, high copper lathecut type amalgam(AM group) and Gallium Alloy GF II (GF group) were used. The fifty extracted sound molars were randomly assigned to AM group and GF group, and the buccal and lingual class V cavities with a size $3{\times}2{\times}2mm$ were prepared. The prepared cavities were randomly assigned to group 1 : no liner used control, group 2 : Copalite, group 3 : Panavia 21, group 4 : All-bond 2, and group 5 : Superbond C&B. After liner placement and amalgam filling, the specimens were stored in $37^{\circ}C$ normal saline for 24 hours and then thermocycled from $5^{\circ}C$ to $55^{\circ}C$ thousand times. The specimens were stored in the 1% methylene blue solution for 24 hours and sectioned and examined by stereomicroscope. The results obtained from this study can be summarized as follows : 1. In the GF group, microleakage values of group 2, 3, 4, 5 were significantly lower than that of group 1 (p<0.05). 2. In the AM group, microleakage values of group 3 and 4 were significantly lower than that of group 1 (p<0.05), but microleakage values of group 2 and 5 did not differ from that of group 1 (p>0.05). 3. The GF group was similar(group, 1 3, 4) or superior(group 2, 5) to the AM group in the aspect of the microleakage.

Salivary proteins which are produced in the saliary acinar cells have been known to be involved in the Calcium and phosphate metabolism. The acquired pellicle resulting from such metabolism is considered as a secondary defence membrane against tooth caries. In this respect, some proteins included in saliva probably play an important role in the prevention of demineralization in enamel. On the other hand, fluoride has long been known to prevent the demineralization of enamel by the inhibition of the growth of Streptococcus mutans(S. mutans) and by the chemical reaction with calcium and phosphate, Therefore, I have examined the roles of amylase and albumin in the demineralization of enamel and compared these preteins with fluoride in terms of anticariogenic effect. 1. The demineralization caused by S. mutans occurred slowly and progressively for the first 60 min, then the rate of demineralization was accelerated afterwards. 2. pH decreased continuously during the entire period of each experiment. 3. The demineralization was significantly inhibited by the preteatment of amylase and fluoride but albumin had little effect on it. 4. An addition of 0.1 mM lactic acid (final concentration 0.1 ${\mu}M$) caused a rapid increase in calcium concentration reaching a maximum within 10 min. 5. pH decreased rapidly by the addition of 0.1 mM lactic acid and reached a minimum within a few seconds followed by an increase in pH. pH reaced a plateu with 10 min. 6. Fluoride, amylase and albumin played little role in the 0.1 mM lactic acid-induced demineralization. 7. A slow infusion of 0.1 M lactic acid at a rate of 5 ${\mu}l/min$ caused a slower increase in calcium concentration compared with the bolus addition of lactic acid. 8. Fluoride had an inhibitory effect on the calcium release caused by slow infusion of lactic acid while amylase and albumin had no effect on it. These results suggest that fluoride inhibits demineralization by protecting the HA from the acid attack whereas amylase has a direct effect on S. mutans to prevent demineralization.

Intracellular pH (pHi) plays an important role in the regulation of cellular processes by influencing the acitivity of various enzymes in cells. Therefore, almost every type of mammalian cell possesses an ability to regulate its pHi. One of the most prominent mechanisms in the regulation of pHi is $Na^+/H^+$ exchanger. This exchanger has been known to be activated when cells are stimulated by the binding of agonist to the muscarinic receptors. Therefore, the aims of this study were to compare the rates of $H^+$ extrusion through $Na^+/H^+$ exchanger before and during muscarinic stimulation and to investigate the possible existence of $HCO_3^-$ transporter which is responsible for the continuous supply of $HCO_3^-$ ion to saliva. Acinar cells were isolated from the rat mandibular salivary glands and loaded with pH-sensitive fluoroprobe, 2', 7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein(BCECF), for 30min at room temperature. Cells were attached onto the coverglass in the perfusion chamber and the changes in pHi were measured on the iverted microscope using spectrofluorometer. 1. By switching the perfusate from $HCO_3^-$-free to $HCO_3^-$-buffered solution, pHi decreased by $0.39{\pm}0.02$ pH units followed by a slow increase at an initial rate of $0.04{\pm}0.007$ pH units/min. The rate of pHi increase was reduced to $0.01{\pm}0.002$ pH units/min by the simultaneous addition of 1 mM amiloride and $100{\mu}M$ DIDS. 2. An addition and removal of $NH_4^+$ caused a decrease in pHi which was followed by an increase in pHi. The increase of pHi was almost completely blocked by 1mM amiloride in $HCO_3^-$-free perfusate which implied that the pHi increase was entired dependent on the activation of $Na^+/H^+$ exchanger in $HCO_3^-$-free condition. 3. An addition of $10{\mu}M$ carbachol increased the initial rate of pHi recovery from $0.16{\pm}0.01$ pH units/min to $0.28{\pm}0.03pH$ units/min. 4. The initial rate of pHi decrease induced by 1mM amiloride was also increased by the exposure of the acinar cells to $10{\mu}M$ carbachol ($0.06{\pm}0.008pH$ unit/min) compared with that obtained before carbachol stimulation ($0.03{\pm}0.004pH$ unit/min). 5. The intracellular buffering capacity ${\beta}1$ was $14.31{\pm}1.82$ at pHi 7.2-7.4 and ${\beta}1$ increased as pHi decreased. 6. The rate of $H^+$ extrusion through $Na^+/H^+$ exchanger was greatly enhanced by the stimulation of the cells with $10{\mu}M$ carbachol and there was an alkaline shift in the activity of the exchanger. 7. An intrusion mechanism of $HCO_3^-$ was identified in rat mandibular salivary acinar cells. Taken all together, I observed 3-fold increase in $Na^+/H^+$ exchanger by the stimulation of the acinar cells with $10{\mu}M$ carbachol at pH 7.25. In addition, I have found an additional mechanism for the regulation of pHi which transported $HCO_3^-$ into the cells.

The purpose of this study is to evaluate and compare the results of argon laser for 5 seconds, argon laser for 10 seconds, and visible light for 40 seconds photo-polymerization in compressive strength, microhardness, curing depth, temperature rising during polymerization, and polymerization shrinkage. Hybrid type composite resin(Z-100) and compomer(Dyract) were used to be compared. The compressive strength was measured by an Instron(1mm/min cross head speed) in 60 specimens and the microhardness of the surface was expressed by Vickers Hardness Number(VHN) in 30 specimens. The curing depth was evaluated comparing the different values of upper and lower VHN according to irradiation time and thickness for the light source polymerization in 60 specimens. The temperature rising during photopolymerization was observed by the temperature change with thermocouple sensitizer beneath 40 specimens at the argon laser for 10 seconds and visible light 40 seconds irradiation. The polymerization shinkage was evaluated by calculating the decrease of % volume by using a dilatometer in 30 specimens. The results were as follows ; 1. In the case of compressive strength, the argon laser polymerization groups were higher than visible light group in Z-100 (p<0.05). In Dyract, the argon laser 5 seconds group did not show a significant difference with the visible light 40 seconds group. The argon laser 10 seconds group showed the markedly low value when compared with other groups (p<0.05) 2. In microhardness, Z-100 was better than Dyract when comparing by VHNs (p<0.05); however, there was not a significant difference between two materials in the visible light 40 seconds group and the argon laser 10 seconds group. 3. In the study of curing depth, Z-100 showed the consistent polymerization in argon laser irradiation because there was no difference in the VHN decrease according to the thickness change. Over the thickness control, the results did not show a significant difference between visible light and argon laser group in Z-100; however, in the case of Dyract, the visible light 40 seconds group was better than the argon laser groups(p<0.05). 4. There was a significant difference between the two materials in temperature rising during polymerization (p<0.05), but not a significant difference between irradiation times, 5. There was not a significant difference between the two materials in polymerization shrink age. The argon laser 5 seconds group was smaller than the other groups (p<0.05). It could be concluded that Z-100 polymerization was recommended to use the argon laser for reduction of the irradiation time while Dyract was recommended to use the visible light polymerization.

Tooth development is usually described in four stages such as bud stage, cap stage, bell stage and crown stage. Exact time of appearance of tooth primordia is different among reports, and up to now there is no timetable regarding initial tooth development. To understand the congenital malformations and other disorders of the orofacial region, there is a need to establish a standard timetable on early tooth development. Till now, studies on the tooth development were mainly on later fetuses, and only few reports on early stage. Also, there were no reports on the time when bud stage turns to cap stage, and cap stage to bell stage. In this study, external morphology of face and the early development of the tooth, and transition of bud stage to cap stage, cap stage to bell stage were studied using 27 staged human embryos and 9 serially sectioned human fetuses. The results are as follows: 1. Mandibular region was formed by union of both mandibular arch at stage 15, and maxillary region by union of maxillary arch, medial nasal prominence, and intermaxillary segment at stage 19. 2. Ectodermal thickening which represents the primordia of tooth appeared in mandibular region at stage 13, and maxillary region at stage 15. 3. Bud stage began from mandibular primary central incisor at stage 17, and maxillary primary central incisor at stage 18. And the sequence of appearance was in the mandibular primary lateral incisor at stage 19, maxillary primary lateral incisor at stage 20, mandibular primary canine at stage 22, maxillary primary canine and primary first molar at stage 23, madibular primary first molar and maxillary primary second molar at 9th week, and mandibular primary second molar at 10th week of development. 4. Cap stage began from the primary anterior teeth at 9th week, and primary second molar still had the characteristics of cap stage at 12th week of development. 5. Transition to bell stage started from the primary anterior teeth at 12th week, and primary second molar started at 16th week of development. 6. Trnasition to crown stage started from primary anterior teeth at 16th week, and primary second molar at 26th week of development.

We already know that it is very difficult to obtain an "isolated field" for direct bonding during the surgical exposure of unerupted teeth. The aim of this in-vitro study is to simulate the clinical situation of forced eruption and to evaluate the tensile strengths of preligatured button with several types of contamination which can happen during the surgical exposure of unerupted teeth. Four orthodontic direct bonding systems were used. ($Ortho-One^{TM}$, $Rely-a-Bond^{(R)}$, $Ortho-Two^{TM}$, Phase $II^{(R)}$) Each material was divided into four groups(n=20) : Group 1. (Control, no contamination), Group 2. (Rinse etching agent with saline instead of water), Group 3. (Blood contamination of etched surface for 30 seconds), Group 4. (Blood contamination of primed surface for 30 seconds) 320 bovine anterior permanent teeth were divided into the above mentioned 16 groups. Enamel surface was flattened and ground under water coolant. Pre-ligatured buttons were prepared to the same form. (Cut 0.25 ligature wire 10 cm in length. Twist the ligature wire 30 times clockwise. Mark the wire 15mm and 35mm points from button. Make a loop sticking two points together and twist the loop 6 times counterclockwise.) The bonded specimens were stored at $37^{\circ}C$ saline solution for 3 days. Then the tensile strength of each sample was measured with Instron universal testing machine, crosshead speed of 0.5mm/min. The following results were obtained: 1. As compared to control groups (Group 1) of each material, Rely-a-Bond had a significantly lower mean tensile strengths than other material. (p<0.01) 2. In Group 2. of Ortho-One and Rely-a-Bond, the mean tensile strengths decreased about 7.7% and 11.1%, respectively with statistical significances. (p<0.05) 3. In Group 2. of Ortho-Two and Phase II, the mean tensile strengths did not decrease. 4. In Group 3. of Ortho-One, Rely-a-Bond, Ortho-Two, and Phase II, the mean tensile strengths decreased about 60.8%, 56.1%, 60.2%, and 46.0%, respectively with statistical significances. (p<0.01) 5. In Group 4. of Ortho-One and Rely-a-Bond, the mean tensile strengths did not decrease. 6. In Group 4. of Ortho-Two and Phase II, the mean tensile strengths were decreased about 20.95% and 22.28%, respectively with statistical significances. (p<0.01) There were formations of a hump shaped mass from bonding resin under blood contamination which disturbed direct bonding procedure. According to Reynolds, the proper bond strength for clinical manipulation should be at least 45N or about 4.5Kg.F. According to these results, it can be concluded that Ortho-One could be used during surgical exposure of unerupted teeth. In any case, blood contamination of the etched surface should be avoided, but the blood contamination of primed surface of Ortho-One may not decrease bond strength. Just 'blowing-out' is enough to remove blood from primed surface of Ortho-One. You can verify the clean surface of the primer of Ortho-One after blowing out the blood contamination.

The purpose of this study was to investigate the effects of syrup medication for asthmatic children on the salivary invertase activity and caries experience. 26 ashmatic children for the study group and 30 healthy children for the control group were selected, respectively. Caries experience was examined and salivary reductase activity was tested. The parents of asthmatic children were asked to fill in the questionaire about syrup intake period and home dental behavior, and the parents of healthy children were asked to fill in the same questionaire without syrup intake period. The results were as follows : 1. The ds index of asthmatic children were higher than that of healthy children(P < 0.05). 2. There was significant difference in dt index between the intake period of 'shorter than 10 months' and 'longer than 20 months'. The ds, dft and dfs indices had a tendency to increase as the intake period increased. 3. The salivary reductase activity had a tendency to increase as the intake period of syrup increased.

This study was performed to establish the cephalometric standards and to compare measurement of Korean children in the Field I, II, III, IV, V, VI to Japanese and Caucasians by the Ricketts' analysis. Lateral cephalograms of 24 males and 27 females with normal occlusion and acceptable profile 9 years of age were obtained and statistically analyzed. 1. Norms of Korean males, females and both sexes at 9 years old were established. 2. Significant differences between male and female exist in incisor overjet, maxillary incisor protrusion, mandibular incisor inclination, cranial deflection, corpus length. Maxillary incisor of male was more protrude and overjet was larger than female 3. Korean was similar to Japanese but different from Caucasian. Compare with facial axis and facial depth, chin was retruded dolichofacial pattern and due to large mandibular plane angle and small corpus length, mandibular plane was inclined and mandible body was short. Compare with porion location, ramus position and posterior facial height, ramus was long and located posterior. Compare with maxillary depth and maxillary height, maxilla was located posterior and inferior. The distance between the upper molar and PTV was short, the amount of distalization is limited. Maxillary and mandibular incisor were more protruded and also lower lip was more protruded to esthetic line 4. In comparison between 9 and 11 years old, growth changes of facial depth, mandibular plane angle, corpus length and upper molar position were larger than that of Japanese and Caucasians.

For the purpose of knowing oral status of handicapped persons and surveying correlative factors, authors interviewed and inspected 259 persons (cerebral palsy 143, mental retardation 101, Down's syndrome 15) from six year to thirty years old in Kwangju. The results were as follows. 1. The dmf rate and dft index of handicapped persons according to age were lower than that of report of normal persons. 2. The DMF rate and DMFT index of handicapped persons increased with age and were similar to or lower than that of report of normal persons by the age of twenty, but were higher after that age. There was no significant difference between handicaps in DMFT rate. 3. Percentage of toothbrushing by himself or herself was 74% in mental retardation, 69% in Down's syndrome, and 48% in cerebral palsy and the frequency of toothbrushing per day of mental retardation, Down's syndrome was higher than that of cerebral palsy. The frequency of toothbrushing per day increased with age. The number of toothbrushing of handicapped persons was slightly higher than that of report of normal persons. 4. Prevalence of gingivitis was 62% in cerebral palsy, 48% in Down's syndrome and 60% in mental retardation. Prevalence of gingivitis increased with age, and was higher than that of report of normal persons. 5. Percentage of tooth anomaly was 15% in Down's syndrome, 8.5% in mental retardation and 4.9% in cerebral palsy. In this study, dental caries of handicapped persons was similar to or lower than that of normal persons and increased with age. The prevalence of gingivitis was much higher in handicapped persons. Subject or frequency of toothbrushing had no influence on the dental caries and gingivitis, education of oral health and system are needed.

The $Papillon-Lef\`{e}vre$ Syndrome(PLS), a disease with autosomal recessive inheritance, is characterized by diffuse hyperkeratosis of the palms and soles, mostly prepubertal periodontitis and premature loss of primary and permanent dentition. The etiology of the destruction of periodontal tissues has not been completely clarified. In recent years, two main factors are suggested to be responsible for tooth loss ; firstly, the presence of gram negative microorganisms in the periodontal pockets of the patients. The other factor suggested is cellular deficiency in chemotaxic and phagocytic function of neutrophylic granulocytes. Resent data suggestes that mechanical debridement in conjunction with antibiotic therapy may be successful in periodontal management of $Papillon-Lef\`{e}vre$ Syndrome, particularly if administered early. In this study, a $Papillon-Lef\`{e}vre$ Syndrome patient was studied clinically, radiologically, histopathologically and microbiologically. 5 years female patient with gingival swelling and destruction of periodontal structure on the whole dentition were examined and palmar and plantar hyperkeratosis were can be seen. On microbiological analysis, Actinobacillus actino-mycetemcomitans was performed. Concurrently, the children recieved extraction of maxillary anterior teeth and construction of removable prosthetis. The combination of professional oral hygiene care and antibiotic therapy improved the dermatologic and periodontal condition.

Non-odontogenic tumors can be classified as malignant or benign. Most oral tumors in children are benign. In the Belfast series only 7.5 percent of soft tissue tumors were malignant and Bhaskar(l963) found only 9 percent of 293 oral tumors of all kinds to be malignant. Benign tumors may be classified as epithelial and mesenchymal. The most common tumor of surface epithelium is the squamous papilloma. These are easily recognized clinically as cauliflower-like lesions. Fibrous lesions are very common in children's mouths. Many of these are not true neoplasms but are related to fibrous hyperplasia. Another common oral tumor in children is angiomatous tumors. Hemangioma occurred more frequently than lymphangioma. Cystic hygroma, a cystic subtype of lymphangioma, is a developmental tumor of lymphatic origin. It is a considered to be a relatively rare lesion. About 50 percent of cystic hygroma are present at birth, and most of the remaining 50 percent appear in the early years of life during the period of active lymphatic growth. The preferred treatment for these lesions, except for hemangioma, is complete surgical excision. With proper surgical techniques, recurrence is not expected.

악안면 영역에 동통이 가하여지면 회피반사의 일종인 개구반사가 유발되며, 개구반사의 크기는 뇌간의 중추에 전달된 동통의 크기에 비례한다. 따라서 동통의 정도를 악이복근의 근전도를 이용하여 정량화 할 수 있고 동통의 지표로 이용할 수 있다. 본 실험은 악안면동통에 의하여 유발된 개구반사의 크기가 침점(족삼리) 전기자극으로 감소되는지와 이러한 전기침의 효과가 나타나는데 opioid 물질이 관여하는지에 대하여 연구하고자 하였다. 8주 이상, 150g이상의 Sprague-Dawley계 쥐 34 마리를 암수 구별없이 이용하여 실험하였다. 복강 내 Urethane용액(1.5g/kg)을 주입 전신마취하고 악이복근을 노출시켜 근전도 기록을 위한 한쌍의 선전극을 삽입하였다. 동통유발을 위하여 구강내 하악 이공주변에 0.1mm의 선전극을 한쌍 삽입하고 전기자극기에 연결하였다. 유해자극 조건은 duration $100{\mu}sec$, interval 5sec의 pulse로 정하고 자극의 크기는 개구반사를 일으키는 역치의 2배 크기로 하며 매 측정시마다 동일 자극을 10회식 가하여 평균하였다. 침점의 전기자극을 위하여 침점의 하나인 족삼리(Zusanli)에 표면전극(넓이 $0.4cm^2$ 정도)을 부착하고 자극부위가 약한 근수축을 일으키는 강도인 $100{\mu}sec$, 5V, 2Hz의 자극을 20분간 가하였다. 악이복근의 근전도는 교류증폭기 (Dam80, WPI, USA) 에서 1000배 증폭하여 유해자극이 가해진 순간 oscilloscope 에서 관찰하여 그 크기를 측정하였다. 침점의 전기자극으로 나타나는 진통효과가 opioid의 분비와 관련있는지 알아보기 위하여 opioid 의 길항제인 naloxone(0.2mg/kg)을 복강 내로 투여하였다. 실험군을 4군(group I - IV)으로 분류하였고 각 군에서 근전도를 측정한 단계는 다음과 같다. group I : control 침점에 전기자극 20 분간 가한후(EA), 20분후(EA20) group II : control 침점에 전기자극 20분간 가한후(EA), naloxone 투여 20분후(NX) group III : control naloxone 투여 5분후 침점에 전기자극 20분 가한후(NxEA20) group IV : control naloxone 투여 20분후(NX20) 구강내에 가해진 유해자극에 의하여 발생하는 악이복근 근전도는 족삼리 침점의 전기자극으로 그 크기가 감소하였고 이러한 침점자극의 효과는 naloxone의 투여로 인하여 억제되었다. 이와 같은 결과는 침점자극으로 진통작용이 나타나는데에 opioid 물질이 관여하고 있음을 시사한다.